This invention relates to a process for purifying wastewater effluent from a wood pulp bleach plant.
The bleaching of wood pulp is necessary to prepare white paper products. Unfortunately, the bleaching process produces a wastewater effluent which contains high levels of color and chlorinated organic compounds.
The wastewater effluent is typically dumped into rivers and lakes. If the effluent is not treated to remove color, the natural color of the river or lake can be adversely affected. If the effluent is not treated to remove chlorinated organics, aquatic life may be destroyed because these compounds are often toxic.
In many instances, the effluent is purified using conventional wastewater treatment. For example, primary treatment can be used to remove a substantial quantity of solid contaminants and secondary and tertiary treatments can be used to remove various organic compounds, particularly nitrogenous compounds. Unfortunately, conventional methods are not only expensive but also inefficient at removing many of the compounds that are toxic and affect color.
Anderson et al., Reactive Polymers, 1 (1982) pp. 67-71, disclose using a macroporous phenolic resin with weakly basic polyamine functionality to purify the wastewater effluent. Unfortunately, the resin is subject to fouling and breakage because of its poor physical stability.
In view of the deficiencies of prior methods, an inexpensive and fficient means is needed for purifying the wastewater effluent from a wood pulp bleach plant.